We present a study on the. formation of p-type ZnO thin film through ion implantation. Group V dopants (N, P) with different ionic radii are implanted into chemical vapor deposition grown ZnO thin film on GaN/sapphire substrates prior to thermal activation. It is found that monodoped ZnO by N+ implantation results in n-type conductivity under thermal activation. Dual-doped ZnO film with a N: P ion implantation dose ratio of 4:1 is found to be p-type under certain thermal activation conditions. Higher p-type activation levels (1019 cm(-3)) under a. wider thermal activation range are found for the N/P dual-doped ZnO film co-implanted by additional oxygen ions. From high resolution x-ray diffraction and x-ray photoelectron spectroscopy it is concluded that the observed p-type conductivities are a result of the promoted formation of P-Zn-4N(O) complex defects via the. concurrent substitution of nitrogen at oxygen sites and phosphorus at zinc sites. The enhanced solubility and stability of acceptor defects in oxygen co-implanted dual-doped ZnO film are related to the reduction of oxygen vacancy defects at the surface. Our study demonstrates the prospect of the. formation of stable p-type ZnO film through co-implantation.